It looks like the display functions in questionnaire have never been brought up to date with the current renderer methods. As far as standard Moodle behavior titles, the multilanguage filter does work on the module title, just not the extra questionnaire title. And from what I can tell, never has. It will also have to be rewritten with the new display functions.
This will unfortunately require a large refactor.
If you want to hack your code in the meantime, here are some changes you can do:
In "/mod/questionnaire/questionnaire.class.php::print_survey_start", line 814, change:
echo '<h3 class="surveyTitle">'.s($this->survey->title).'</h3>';
to
echo '<h3 class="surveyTitle">'.format_text($this->survey->title, FORMAT_HTML).'</h3>';
In "/mod/questionnaire/questionnaire.class.php::questionstart_survey_display", line 931, change:
echo format_text(file_rewrite_pluginfile_urls($this->content, 'pluginfile.php',
$this->context->id, 'mod_questionnaire', 'question', $this->id), FORMAT_HTML);
to
$options = array('noclean' => true, 'para' => true, 'filter' => true, 'context' => $this->context, 'overflowdiv' => true);
echo format_text(file_rewrite_pluginfile_urls($this->content, 'pluginfile.php',
$this->context->id, 'mod_questionnaire', 'question', $this->id), FORMAT_HTML, $options);
mike